The present invention relates to an apparatus and a method for bonding electronic components to a circuit board by using a heating source, a circuit board manufactured by the method, and an electronic component mounting apparatus having a bonder for an electronic component, and more particularly, relates to an apparatus and a method for bonding electronic components so as to manufacture compact and thin circuit boards to be used in compact mobile devices, a circuit board manufactured by the method, and an electronic component mounting apparatus.
In a liquid crystal module used for a mobile device or the like, electronic components are mounted to a flexible substrate (FPC) so as to control display of a liquid crystal display part and electrically connect a liquid crystal module to a mother board. To the FPC are mounted a driver IC for the above display control, and chip components such as capacitors, and the like. Since connection parts of the driver IC have narrow pitches, and contamination of the connection parts causes a decrease of reliability of the liquid crystal module, the driver IC is normally mounted before the chip components are mounted.
After the driver IC is mounted, as shown in FIG. 19, solder is supplied onto the FPC by a solder printer 1 and, chip components are mounted onto the FPC by a component mounting machine 2. Then, the FPC is carried into a reflow apparatus 3 having a heat source for melting the solder, whereby the solder is melted and the chip components are bonded to the FPC. In this case, if a circuit board has a thickness of approximately 1 mm and rigidity, the circuit board can be belt transferred by a conveyor. However, in a case of a flexible and film-shaped circuit board, e.g., the above FPC, as shown in FIG. 20, a method is employed in which FPCs 5 are aligned and fixed on a pallet 4, transferred and carried into the reflow apparatus 3. The reflow apparatus 3 at this time is a reflow apparatus which heats an environment in a furnace and then on the pallet 4, causes soldering operations on the FPCs 5 to be performed together.
In producing FPCs 5 of different kinds, each kind of FPC 5 on which components corresponding to each kind are mounted is transferred to the reflow apparatus. But, the reflow apparatus, which heats the environment in the furnace, has poor productivity in this case, and it is more efficient to heat only necessary portions. As such, a reflow apparatus using local heating by providing a light beam system as shown in FIG. 21 is effective. Particularly for preventing light from being applied to other than necessary portions, an arrangement is effective whereby light emitted from a light irradiation part 11 is applied only to the necessary portions through an opening 13 of a mask 12. Reference numeral 6, reference numeral 7 and reference numeral 8 in FIG. 21 indicate a chip component, IC and solder, respectively.
In producing many FPCs 5 of the same kind, productivity is improved by arranging the FPCs 5 on a pallet 4 as large as possible and executing bonding by solder on the FPCs 5 at a single time. However, there is little time in many cases, lately from determining specifications of a circuit board, to produce the circuit board because of a short life of goods, a variety of kinds, complication of design due to sophistication of functions, and fluidity of market trends, and consequently a mass production method by using a large pallet 4 cannot meet enhancing production efficiency requirements.
The production equipment indicated in FIG. 19 is based on a condition of treating large substrates, and therefore each apparatus is itself large. Particularly, the reflow apparatus which heats the environment in the furnace generally has a length of 3-5 m because of uniform heating, and the equipment is too large with respect to a circuit board having a size of approximately 2-30 mm, thereby obstructing flexible measures. The system with the solder printer 1, the component mounting machine 2 and the reflow apparatus 3 shown in FIG. 19 has a total length of as long as, e.g., 7 m.
Although the light beam system is effective in a case of components of the same kind or a small number of components, the number of chip components 6 and the number of kinds of chip components on an FPC 5 tend to increase these days in accordance with an enhanced level of function of the liquid crystal module, and therefore, setting an irradiation condition or the like becomes difficult when there are components having different light absorptances on the FPC 5. For instance, it is possible to manipulate a condition of the mask 12 for black electronic components or electronic components that are to be slightly heated, but there is a limitation imposed on meeting every component by the mask 12 alone because an adjacent solder is half melted or the like.
The present invention is devised to solve the above problems and has for its object to provide an apparatus and a method for bonding electronic components, which enable manufacturing a large number of kinds of circuit boards, each by a small amount, with a higher productivity than in the conventional art, circuit boards manufactured by the method, and an electronic component mounting apparatus having a bonder for an electronic component.
In order to accomplish the above objective, the present invention is constituted as follows.
A bonder for an electronic component of a first aspect of the present invention comprises:
a stage member for having placed thereon a circuit board to have electronic components mounted thereto; and
a heating device for heating the stage member so as to heat the circuit board held in contact with the stage member, and melt a bonding material for bonding the electronic components and the circuit board to each other.
A bonder for an electronic component of a second aspect of the present invention comprises:
a plurality of stage members for having placed thereon a circuit board to have electronic components mounted thereto; and
a heating device provided for each of the stage members for heating its stage member so as to heat the circuit board held in contact with this stage member, and melt a bonding material for bonding the electronic components and the circuit board to each other.
In the above first and second aspects, there can be provided a suction device connected to the stage member(s) for sucking and holding the circuit board to the stage member(s).
Also in the first and second aspects, a rear face of each stage member which comes into contact with its respective heating device, and this heating device, can define a space for suction to allow the stage member to be sucked by the suction device.
Further in the first and second aspects, each stage member can have an opening for suction which connects the suction device directly to each stage member.
In the first and second aspects, each stage member can also have a substrate suction hole for sucking a suction region at a stage member contact face of the circuit board held in contact with this stage member, and which connects with the opening for suction.
Yet further in the first and second aspects, there can be provided a member for adhesion to be held between each stage member and its respective heating device for adhering the stage member and the heating device to each other, and a suction device for each stage member which is connected to each heating device for sucking and holding the stage member to its heating device via the member for adhesion by performing a suction operation.
Still in the first and second aspects, an adhesion member contact face of each stage member held in contact with its respective member for adhesion, and this member for adhesion, can define a space for suction to allow the stage member to be sucked by the suction device for the stage member.
In the first and second aspects, each heating device can include a ceramic heater and heat the circuit board by changing a heating temperature with respect to a heating time.
Again in the first and second aspects, there can be provided a cooling device, to be connected to the heating device, for cooling the circuit board.
In an electronic component bonding method according to a third aspect of the present invention, the method comprises:
heating a circuit board that is to have electronic components bonded thereto by a bonding material, with the circuit board being placed on a stage member so as to be in contact therewith, and
melting the bonding material by the heating.
A circuit board of a fourth aspect of the present invention is a circuit board having electronic components bonded thereto by performing the electronic component bonding method of the above third aspect.
An electronic component mounting apparatus of a fifth aspect of the present invention comprises the bonder for an electronic component of the first aspect or the second aspect.
According to the bonder for an electronic component of the first and second aspects, the electronic component bonding method of the third aspect and the electronic component mounting apparatus of the fifth aspect of the present invention described above, there are provided the stage member(s) and the heating device(s), wherein the circuit board is brought into contact with the stage member(s) having a size almost equal to a size of one circuit board, and heated by the heating device(s), thus enabling individual heating corresponding to each of various kinds of circuit boards as well as reducing generation of losses with regard to compact circuit boards. Many kinds of circuit boards can be manufactured, each by a small amount, with a higher productivity as compared with the conventional art.
In addition, the suction device for sucking and holding the circuit board to the stage member(s) enables the circuit board to be tightly adhered to the stage member(s), so that a temperature control of the circuit board can be carried out more accurately.
Each stage member has the opening for suction which directly connects to the suction device, thereby preventing bonding material from contaminating the heating device(s) when the bonding material is melted. A cleaning operation for each heating device is eliminated and an availability rate of the bonder for an electronic component can be improved accordingly.
When there are provided the member(s) for adhesion and the suction device for the stage member(s), the stage member(s) can be sucked and held to the heating device(s) by suction action of the suction device for the stage member. Also, when the member(s) for adhesion are arranged, adhesion of the stage member(s) to the heating device(s) can be improved at a time of suction and holding.
When the adhesion member(s)""contact face(s) and the member(s) for adhesion have a space for suction, a suction force of the stage member(s) relative to the heating device(s) can be improved.
When the ceramic heater is used for each heating device, responsiveness to a temperature rise/fall at the heating device can be improved. In consequence, heating by an appropriate temperature control is enabled for each of various kinds of circuit boards. Responsiveness to a temperature change at each heating device can be improved also by including the cooling device, thus enabling heating by an appropriate temperature control for each of various kinds of circuit boards.
Regarding circuit boards having a thickness of not larger than 1 mm, or film-shaped circuit boards, these circuit boards have a good temperature responsiveness to heating control of the heating device. Therefore, heating by an appropriate temperature control is enabled for each of various kinds of circuit boards.
It can be arranged so that one circuit board is heated by a plurality of stage members. A change in size of various kinds of circuit boards can be easily responded to by employing this arrangement, whereby heating by an appropriate temperature control for each of various kinds of circuit boards is enabled.
According to the circuit board of the fourth aspect of the present invention, onto which the electronic components are bonded by the bonder of the first and second aspects, the electronic component bonding method of the third aspect and the electronic component mounting apparatus of the fifth aspect, since heating is performed by an appropriate temperature control corresponding to each kind of board, a bonding state of electronic components can be made uniform for each kind of board.